A variety of industrial processes comprise one or more process steps which require the use of a chemical reactor. Such a process step may involve, for example, a chemical reaction, gas absorption, distillation or the like.
Many types of reactors are known. Batch reactors involve a reactor chamber in which, once fluid particles, e.g. the reactants, have been added to the chamber, flow neither enters nor leaves the reactor. The contents are mixed until the reaction is complete and then the reactor is emptied and the process repeated.
A plug flow reactor is one in which fluid particles enter, pass through and are discharged from the reactor in the same sequence. In such a reactor, all of the fluid particles remain in the reactor for about the same length of time.
In a continuous stirred tank reactor (CSTR), particles entering the reactor are dispersed immediately throughout the reactor. Accordingly, the particles are discharged from the tank in proportion to their statistical population. In this type of reactor, all fluid particles do not have about the same retention time within the reactor.
Packed bed reactors are reactors which are filled with a packing media, such as rocks or gravel or shaped packings such as saddles, rings, stars, and the like. The packing media increases the surface area within the reactor and increases turbulence of the fluid particles flowing through the reactor.
In many processes, it is desirable to maximize the residence time of all fluid particles within the reactor. This is particularly true in the case of gas-exchange reactions, such as the absorption of gas by a liquid. Maximum residence time is typically achieved by plug flow. However, plug flow is difficult to achieve in gas-exchange reactions which are typically carried out in reactors exhibiting CSTR flow characteristics.